The invention pertains to the field of electronic document storage and recovery systems, and, more particularly, to the field of compressed image expanders used in such systems.
With the growing volume of documentation in the business community, the space taken up by millions of documents and the labor of retrieving them are becoming non-trivial expenses. In an effort to more efficiently deal with such large volumes of documents, electronic document storage and retrieval systems have been and are being developed. The object of these systems is to electronically scan a document into a bit mapped image stored in a frame buffer. Compressing circuitry then compresses the document image to reduce the amount of data that must be stored. When the document is to be retrieved for display or printing, the compressed data is retrieved and expanded by a compressed image expansion system.
Such image expansion systems must be able to efficiently and rapidly handle large quantities of data since images contain huge volumes of data. Further, such systems must be flexible enough to rapidly large quantities of data which is totally unpredictable in its format. Several stages in the expansion or decoding process must occur. Usually, one function cannot occur until the preceding function has occurred. Since each document image may be different and unpredictable, it is impossible to predict how long each stage will need to complete its task. Problems in system operational speed will occur if such a data environment causes the image expansion system to bog down in terms of the speed with which an image is expanded from its compressed form. Thus a need has arisen for an compressed image expansion system which can rapidly handle large volumes of data in whatever format it arrives.